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van der Ven AT, Johannsen J, Kortüm F, Wagner M, Tsiakas K, Bierhals T, Lessel D, Herget T, Kloth K, Lisfeld J, Scholz T, Obi N, Wortmann S, Prokisch H, Kubisch C, Denecke J, Santer R, Hempel M. Prevalence and clinical prediction of mitochondrial disorders in a large neuropediatric cohort. Clin Genet 2021; 100:766-770. [PMID: 34490615 DOI: 10.1111/cge.14061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/17/2021] [Accepted: 09/02/2021] [Indexed: 11/29/2022]
Abstract
Neurological symptoms are frequent and often a leading feature of childhood-onset mitochondrial disorders (MD) but the exact incidence of MD in unselected neuropediatric patients is unknown. Their early detection is desirable due to a potentially rapid clinical decline and the availability of management options. In 491 children with neurological symptoms, a comprehensive diagnostic work-up including exome sequencing was performed. The success rate in terms of a molecular genetic diagnosis within our cohort was 51%. Disease-causing variants in a mitochondria-associated gene were detected in 12% of solved cases. In order to facilitate the clinical identification of MDs within neuropediatric cohorts, we have created an easy-to-use bedside-tool, the MDC-NP. In our cohort, the MDC-NP predicted disease conditions related to MDs with a sensitivity of 0.83, and a specificity of 0.96.
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Affiliation(s)
- Amelie T van der Ven
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jessika Johannsen
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Matias Wagner
- Institute of Human Genetics, Klinikum Rechts der Isar, TUM, Munich, Germany.,Institute of Neurogenomics, Helmholtz Center Munich, Neuherberg, Germany
| | - Konstantinos Tsiakas
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Davor Lessel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Theresia Herget
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katja Kloth
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jasmin Lisfeld
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tasja Scholz
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nadia Obi
- Institute of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Saskia Wortmann
- Institute of Human Genetics, Klinikum Rechts der Isar, TUM, Munich, Germany.,Institute of Neurogenomics, Helmholtz Center Munich, Neuherberg, Germany.,Department of Pediatrics, University Medical Center Salzburg, Salzburg, Austria
| | - Holger Prokisch
- Institute of Human Genetics, Klinikum Rechts der Isar, TUM, Munich, Germany.,Institute of Neurogenomics, Helmholtz Center Munich, Neuherberg, Germany
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Martin Zeitz Center of Rare Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jonas Denecke
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Martin Zeitz Center of Rare Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Martin Zeitz Center of Rare Diseases, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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2
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Zuccolotto-Dos-Reis FH, Escarso SHA, Araujo JS, Espreafico EM, Alberici LC, Sobreira CFDR. Acetyl-CoA-driven respiration in frozen muscle contributes to the diagnosis of mitochondrial disease. Eur J Clin Invest 2021; 51:e13574. [PMID: 33937992 DOI: 10.1111/eci.13574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/09/2021] [Accepted: 04/11/2021] [Indexed: 01/22/2023]
Abstract
BACKGROUND Freezing human biopsies is common in clinical practice for storage. However, this technique disrupts mitochondrial membranes, hampering further analyses of respiratory function. To contribute to laboratorial diagnosis of mitochondrial diseases, this study sought to develop a respirometry approach using O2k (Oroboros Ins.) to measure the whole electron transport chain (ETC) activity in homogenates of frozen skeletal muscle biopsies. PATIENTS AND METHODS We enrolled 16 patients submitted to muscle biopsy in the process of routine diagnostic investigation: four with mitochondrial disease and severe mitochondrial dysfunction; seven with exercise intolerance and multiple deletions of mitochondrial DNA, presenting mild to moderate mitochondrial dysfunction; five without mitochondrial disease, as controls. Whole homogenates of muscle fragments were prepared using grinder-type equipment. O2 consumption rates were normalized using citrate synthase activity. RESULTS Transmission electron microscopy confirmed mitochondrial membrane discontinuation, indicating increased permeability of mitochondrial membranes in homogenates from frozen biopsies. O2 consumption rates in the presence of acetyl-CoA lead to maximum respiratory rates sensitive to rotenone, malonate and antimycin. This protocol of acetyl-CoA-driven respiration (ACoAR), applied in whole homogenates of frozen muscle, was sensitive enough to identify ETC abnormality, even in patients with mild to moderate mitochondrial dysfunction. We demonstrated adequate repeatability of ACoAR and found significant correlation between O2 consumption rates and enzyme activity assays of individual ETC complexes. CONCLUSIONS We present preliminary data on a simple, low cost and reliable procedure to measure respiratory function in whole homogenates of frozen skeletal muscle biopsies, contributing to diagnosis of mitochondrial diseases in humans.
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Affiliation(s)
| | - Silvia Helena Andrião Escarso
- Department of Neurosciences, Division of Neurology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Jackeline Souza Araujo
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Enilza Maria Espreafico
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Luciane Carla Alberici
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
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3
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Frazier AE, Vincent AE, Turnbull DM, Thorburn DR, Taylor RW. Assessment of mitochondrial respiratory chain enzymes in cells and tissues. Methods Cell Biol 2019; 155:121-156. [PMID: 32183956 DOI: 10.1016/bs.mcb.2019.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Measurement of the individual enzymes involved in mitochondrial oxidative phosphorylation (OXPHOS) forms a key part of diagnostic investigations in patients with suspected mitochondrial disease, and can provide crucial information on mitochondrial OXPHOS function in a variety of cells and tissues that are applicable to many research investigations. In this chapter, we present methods for analysis of mitochondrial respiratory chain enzymes in cells and tissues based on assays performed in two geographically separate diagnostic referral centers, as part of clinical diagnostic investigations. Techniques for sample preparation from cells and tissues, and spectrophotometric assays for measurement of the activities of OXPHOS complexes I-V, the combined activity of complexes II+III, and the mitochondrial matrix enzyme citrate synthase, are provided. The activities of mitochondrial respiratory chain enzymes are often expressed relative to citrate synthase activity, since these ratios may be more robust in accounting for variability that may arise due to tissue quality, handling and storage, cell growth conditions, or any mitochondrial proliferation that may be present in tissues from patients with mitochondrial disease. Considerations for adaption of these techniques to other cells, tissues, and organisms are presented, as well as comparisons to alternate methods for analysis of respiratory chain function. In this context, a quantitative immunofluorescence protocol is also provided that is suitable for measurement of the amount of multiple respiratory chain complexes in small diagnostic tissue samples. The analysis and interpretation of OXPHOS enzyme activities are then placed in the context of mitochondrial disease tissue pathology and diagnosis.
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Affiliation(s)
- Ann E Frazier
- Brain and Mitochondrial Research, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Amy E Vincent
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David R Thorburn
- Brain and Mitochondrial Research, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia; Victorian Clinical Genetics Services, Melbourne, VIC, Australia
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; NHS Highly Specialised Mitochondrial Diagnostic Laboratory, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom.
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4
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Napoli E, Schneider A, Hagerman R, Song G, Wong S, Tassone F, Giulivi C. Impact of FMR1 Premutation on Neurobehavior and Bioenergetics in Young Monozygotic Twins. Front Genet 2018; 9:338. [PMID: 30210529 PMCID: PMC6119880 DOI: 10.3389/fgene.2018.00338] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/08/2018] [Indexed: 01/18/2023] Open
Abstract
Mitochondrial dysfunction (MD) has been identified in lymphocytes, fibroblasts and brain samples from adults carrying a 55-200 CGG expansion in the fragile X mental retardation 1 (FMR1) gene (premutation; PM); however, limited data are available on the bioenergetics of pediatric carriers. Here we discuss a case report of three PM carriers: two monozygotic twins (aged 8 years) harboring an FMR1 allele with 150-180 CGG repeats, with no cognitive or intellectual issues but diagnosed with depression, mood instability and ADHD, and their mother (asymptomatic carrier with 78 CGG repeats). Fibroblasts and lymphocytes from the twins presented a generalized OXPHOS deficit, altered mitochondrial network, accumulation of depolarized mitochondria, and increased mitochondrial ROS production, outcomes distinct and more severe than the mother's ones, suggesting the involvement of modulatory effects mediated by CGG expansion, X-activation ratio, sex hormones and epigenetic factors (chronic inflammation, consequence of Lyme disease). The degree of the severity of MD appeared to segregate with the morbidity of the phenotype. The mitochondrial ROS-mediated HIF-1α stabilization was identified as a key player at contributing to the MD, pointing it as a novel target for future therapeutical intervention.
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Affiliation(s)
- Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Andrea Schneider
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, United States
- Department of Pediatrics, School of Medicine, University of California, Davis, Sacramento, CA, United States
| | - Randi Hagerman
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, United States
- Department of Pediatrics, School of Medicine, University of California, Davis, Sacramento, CA, United States
| | - Gyu Song
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Sarah Wong
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Flora Tassone
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, United States
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, United States
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
- UC Davis MIND Institute, UC Davis Health, Sacramento, CA, United States
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5
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Erdol S, Saglam H. Outcomes of mitochondrial derived diseases: a single-center experience. J Pediatr Endocrinol Metab 2018; 31:399-405. [PMID: 29614848 DOI: 10.1515/jpem-2017-0405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/22/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND The purpose of this study is to help elucidate which part of the mitochondria is causing a problem through anamnesis, physical examination, and routine biochemical tests in the event of a suspected mitochondrial disease case. METHODS The data were obtained retrospectively from the medical records of 75 cases; the mitochondrial-derived disease (MDD) cases were observed in our center from 2011 to 2017. RESULTS The most commonly observed MDDs were oxidative phosphorylation disorders at 44%, followed by fatty acid oxidation disorder at 40%, pyruvate metabolism disorder at 12%, and ketone metabolism disorder at 4%, respectively. The most common clinical presentation at the time of referral to the hospital was metabolic acidosis (20%), and the most common symptom was respiratory distress (24%). There were abnormal findings in 84.3% of the cases subjected to cranial magnetic resonance imaging (MRI), with the most common being hyperintensity in the bilateral basal ganglia (49.0%). CONCLUSIONS Anamnesis, physical examination, and simple laboratory data could provide some important clues in assessing MDD. Blood gas should definitely be measured in cases with respiratory symptoms, particularly if they have a history of consanguineous marriage or a sibling suffering from a similar disease. If metabolic acidosis exists in the blood gas, MDDs should absolutely be included in the differential diagnosis. Furthermore, ophthalmic and cardiac assessment and cranial MRI will also reveal significant data for diagnosing MDDs.
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Affiliation(s)
- Sahin Erdol
- Uludag University Faculty of Medicine, Department of Pediatrics, Division of Metabolism, Bursa, Turkey
| | - Halil Saglam
- Uludag University Faculty of Medicine, Department of Pediatrics, Division of Metabolism, Bursa, Turkey
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6
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McAfee JL, Warren CB, Prayson RA. Ultrastructural examination of skin biopsies may assist in diagnosing mitochondrial cytopathy when muscle biopsies yield negative results. Ann Diagn Pathol 2017; 29:41-45. [PMID: 28807341 DOI: 10.1016/j.anndiagpath.2017.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 11/16/2022]
Abstract
Ultrastructural evaluation of skin biopsies has been utilized for diagnosis of mitochondrial disease. This study investigates how frequently skin biopsies reveal mitochondrial abnormalities, correlates skin and muscle biopsy findings, and describes clinical diagnoses rendered following the evaluation. A retrospective review of surgical pathology reports from 1990 to 2015 identified skin biopsies examined by electron microscopy for suspected metabolic disease. A total of 630 biopsies were included from 615 patients. Of these patients, 178 also underwent a muscle biopsy. Of the 630 skin biopsies, 75 (12%) showed ultrastructural abnormalities and 34 (5%) specifically showed mitochondrial abnormalities including increased size (n=27), reduced or abnormal cristae (n=23), dense matrices (n=20), and increased number (n=8). Additional findings included lysosomal abnormalities (n=13), lipid accumulation (n=2) or glycogen accumulation (n=1). Of the 34 patients with mitochondrial abnormalities on skin biopsy, 20 also had muscle biopsies performed and nine showed abnormalities suggestive of a mitochondrial disorder including absent cytochrome oxidase staining (n=2), increased subsarcolemmal NADH, SDH, or cytochrome oxidase staining (n=1), or ultrastructural findings including large mitochondrial size (n=5), abnormal mitochondrial structure (n=5), and increased mitochondrial number (n=4). The most common presenting symptoms were intellectual disability (n=13), seizures (n=12), encephalopathy (n=9), and gastrointestinal disturbances (n=9). At last known follow-up, 12 patients had a definitive diagnosis of a mitochondrial disorder. One patient each had Complex I deficiency, Complex III deficiency, Charcot-Marie-Tooth disease, pyruvate dehydrogenase deficiency, and Phelan-McDermid syndrome. Our results suggest that skin biopsy sometimes yields diagnostic clues suggestive of a mitochondrial cytopathy in cases with a negative muscle biopsy.
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Affiliation(s)
- John L McAfee
- Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | | | - Richard A Prayson
- Department of Anatomic Pathology, Cleveland Clinic, Cleveland, OH, USA.
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7
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Phadke R. Myopathology of Adult and Paediatric Mitochondrial Diseases. J Clin Med 2017; 6:jcm6070064. [PMID: 28677615 PMCID: PMC5532572 DOI: 10.3390/jcm6070064] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 06/21/2017] [Accepted: 06/28/2017] [Indexed: 01/09/2023] Open
Abstract
Mitochondria are dynamic organelles ubiquitously present in nucleated eukaryotic cells, subserving multiple metabolic functions, including cellular ATP generation by oxidative phosphorylation (OXPHOS). The OXPHOS machinery comprises five transmembrane respiratory chain enzyme complexes (RC). Defective OXPHOS gives rise to mitochondrial diseases (mtD). The incredible phenotypic and genetic diversity of mtD can be attributed at least in part to the RC dual genetic control (nuclear DNA (nDNA) and mitochondrial DNA (mtDNA)) and the complex interaction between the two genomes. Despite the increasing use of next-generation-sequencing (NGS) and various omics platforms in unravelling novel mtD genes and pathomechanisms, current clinical practice for investigating mtD essentially involves a multipronged approach including clinical assessment, metabolic screening, imaging, pathological, biochemical and functional testing to guide molecular genetic analysis. This review addresses the broad muscle pathology landscape including genotype–phenotype correlations in adult and paediatric mtD, the role of immunodiagnostics in understanding some of the pathomechanisms underpinning the canonical features of mtD, and recent diagnostic advances in the field.
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Affiliation(s)
- Rahul Phadke
- Division of Neuropathology, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London WC1N 3BG, UK.
- Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK.
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8
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Sonam K, Bindu PS, Srinivas Bharath MM, Govindaraj P, Gayathri N, Arvinda HR, Chiplunkar S, Nagappa M, Sinha S, Khan NA, Nunia V, Paramasivam A, Thangaraj K, Taly AB. Mitochondrial oxidative phosphorylation disorders in children: Phenotypic, genotypic and biochemical correlations in 85 patients from South India. Mitochondrion 2016; 32:42-49. [PMID: 27826120 DOI: 10.1016/j.mito.2016.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 10/12/2016] [Accepted: 11/03/2016] [Indexed: 12/13/2022]
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) disorders account for a variety of neuromuscular disorders in children. In this study mitochondrial respiratory chain enzymes were assayed in muscle tissue in a large cohort of children with varied neuromuscular presentations from June 2011 to December 2013. The biochemical enzyme deficiencies were correlated with the phenotypes, magnetic resonance imaging, histopathology and genetic findings to reach a final diagnosis. There were 85 children (mean age: 6.9±4.7years, M:F:2:1) with respiratory chain enzyme deficiency which included: isolated complex I (n=50, 60%), multiple complexes (n=24, 27%), complex IV (n=8, 9%) and complex III deficiencies (n=3, 4%). The most common neurological findings were ataxia (59%), hypotonia (59%) and involuntary movements (49%). A known mitochondrial syndrome was diagnosed in 27 (29%) and non-syndromic presentations in 57 (71%). Genetic analysis included complete sequencing of mitochondrial genome, SURF1, POLG1&2. It revealed variations in mitochondrial DNA (n=8), SURF1 (n=5), and POLG1 (n=3). This study, the first of its kind from India, highlights the wide range of clinical and imaging phenotypes and genetic heterogeneity in children with mitochondrial oxidative phosphorylation disorders.
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Affiliation(s)
- Kothari Sonam
- Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Parayil Sankaran Bindu
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India.
| | - M M Srinivas Bharath
- Department of Neurochemistry, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Periyasamy Govindaraj
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Narayanappa Gayathri
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Hanumanthapura R Arvinda
- Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Shwetha Chiplunkar
- Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Madhu Nagappa
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | - Sanjib Sinha
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
| | | | - Vandana Nunia
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | | | - Arun B Taly
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India; Neuromuscular Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
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9
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Abstract
Mitochondrial diseases are a clinically heterogeneous group of disorders that ultimately result from dysfunction of the mitochondrial respiratory chain. There is some evidence to suggest that mitochondrial dysfunction plays a role in neuropsychiatric illness; however, the data are inconclusive. This article summarizes the available literature published in the area of neuropsychiatric manifestations in both children and adults with primary mitochondrial disease, with a focus on autism spectrum disorder in children and mood disorders and schizophrenia in adults.
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Affiliation(s)
- Samantha E Marin
- Department of Neurosciences, University of California, San Diego (UCSD), 9500 Gilman Drive #0935, La Jolla, CA 92093-0935, USA
| | - Russell P Saneto
- Department of Neurology, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way Northeast, Seattle, WA 98105, USA; Department of Pediatrics, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way Northeast, Seattle, WA 98105, USA.
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10
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Guarani V, Jardel C, Chrétien D, Lombès A, Bénit P, Labasse C, Lacène E, Bourillon A, Imbard A, Benoist JF, Dorboz I, Gilleron M, Goetzman ES, Gaignard P, Slama A, Elmaleh-Bergès M, Romero NB, Rustin P, Ogier de Baulny H, Paulo JA, Harper JW, Schiff M. QIL1 mutation causes MICOS disassembly and early onset fatal mitochondrial encephalopathy with liver disease. eLife 2016; 5. [PMID: 27623147 PMCID: PMC5021520 DOI: 10.7554/elife.17163] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/24/2016] [Indexed: 12/16/2022] Open
Abstract
Previously, we identified QIL1 as a subunit of mitochondrial contact site (MICOS) complex and demonstrated a role for QIL1 in MICOS assembly, mitochondrial respiration, and cristae formation critical for mitochondrial architecture (Guarani et al., 2015). Here, we identify QIL1 null alleles in two siblings displaying multiple clinical symptoms of early-onset fatal mitochondrial encephalopathy with liver disease, including defects in respiratory chain function in patient muscle. QIL1 absence in patients' fibroblasts was associated with MICOS disassembly, abnormal cristae, mild cytochrome c oxidase defect, and sensitivity to glucose withdrawal. QIL1 expression rescued cristae defects, and promoted re-accumulation of MICOS subunits to facilitate MICOS assembly. MICOS assembly and cristae morphology were not efficiently rescued by over-expression of other MICOS subunits in patient fibroblasts. Taken together, these data provide the first evidence of altered MICOS assembly linked with a human mitochondrial disease and confirm a central role for QIL1 in stable MICOS complex formation.
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Affiliation(s)
- Virginia Guarani
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Claude Jardel
- Inserm U1016, Institut Cochin, CNRS UMR 8104, Paris, France.,Department of Biochemistry, APHP, GHU Pitié-Salpêtrière, Paris, France.,Université Paris-Descartes, Paris, France
| | - Dominique Chrétien
- UMR1141, PROTECT, INSERM, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Anne Lombès
- Inserm U1016, Institut Cochin, CNRS UMR 8104, Paris, France.,Department of Biochemistry, APHP, GHU Pitié-Salpêtrière, Paris, France.,Université Paris-Descartes, Paris, France
| | - Paule Bénit
- UMR1141, PROTECT, INSERM, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Clémence Labasse
- Neuromuscular morphology unit, Institut de Myologie, GHU Pitié-Salpêtrière, APHP, Paris, France
| | - Emmanuelle Lacène
- Neuromuscular morphology unit, Institut de Myologie, GHU Pitié-Salpêtrière, APHP, Paris, France
| | - Agnès Bourillon
- Department of Biochemistry, Hôpital Robert Debré, APHP, Paris, France
| | - Apolline Imbard
- Department of Biochemistry, Hôpital Robert Debré, APHP, Paris, France
| | | | - Imen Dorboz
- UMR1141, PROTECT, INSERM, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Mylène Gilleron
- Inserm U1016, Institut Cochin, CNRS UMR 8104, Paris, France.,Department of Biochemistry, APHP, GHU Pitié-Salpêtrière, Paris, France.,Université Paris-Descartes, Paris, France
| | - Eric S Goetzman
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, United States.,University of Pittsburgh, Pittsburgh, United States.,Children's Hospital of Pittsburgh of UPMC, Pittsburgh, United States
| | - Pauline Gaignard
- Department of Biochemistry, Hôpital Bicêtre, APHP, Paris, France
| | - Abdelhamid Slama
- Department of Biochemistry, Hôpital Bicêtre, APHP, Paris, France
| | | | - Norma B Romero
- Neuromuscular morphology unit, Institut de Myologie, GHU Pitié-Salpêtrière, APHP, Paris, France
| | - Pierre Rustin
- UMR1141, PROTECT, INSERM, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Hélène Ogier de Baulny
- Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - J Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Manuel Schiff
- UMR1141, PROTECT, INSERM, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France.,Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
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11
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Shatla HM, Tomoum HY, Elsayed SM, Elagouza IA, Shatla RH, Mohsen MM, Hamed AN. Role of plasma amino acids and urinary organic acids in diagnosis of mitochondrial diseases in children. Pediatr Neurol 2014; 51:820-5. [PMID: 25456303 DOI: 10.1016/j.pediatrneurol.2014.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/03/2014] [Accepted: 08/13/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND Diagnostic difficulty in mitochondrial diseases (MD) results not only from the wide spectrum of symptoms and signs but also from the absence of a reliable screening or diagnostic biomarker. AIM To investigate the likelihood of MD in patients with symptoms and signs impressive of MD through quantitative measurement of plasma amino acids, and urinary organic acids. METHODS Twenty patients with symptoms and signs suggestive of MD were further evaluated by quantitative plasma amino acids and urinary organic acids assay and neuroimaging. RESULTS Plasma amino acid results revealed elevation of alanine in 11, glycine in five, and proline in two patients. Abnormal urinary organic acid analysis was present in six patients; increased urinary lactate (20%), dicarboxylicaciduria (15%), and urinary ketone bodies (10%). Upon enrollment our patients scored as possible MD according to the MD scoring system. At the end of the study, five patients still scored as possible MD, eight patients as probable MD, and seven patients as definite MD. All patients with definite MD had elevated serum lactate. In three patients, elevated urinary lactate was the only abnormality. Alanine was elevated in all patients with definite MD, whereas proline was elevated in only one. Magnetic resonance imaging of the brain showed atrophic changes in one patient and bilateral basal ganglia hyperintensity in another. CONCLUSION Urinary organic acids and quantitative plasma amino acids can help in the diagnosis of MD, especially when the economic burden and absence of specialized centers limits the diagnosis.
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Affiliation(s)
- Hamed M Shatla
- Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Hoda Y Tomoum
- Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Solaf M Elsayed
- Department of Genetics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Iman A Elagouza
- Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
| | - Rania H Shatla
- Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Mostafa M Mohsen
- Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Ashraf N Hamed
- Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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12
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Habarou F, Brassier A, Rio M, Chrétien D, Monnot S, Barbier V, Barouki R, Bonnefont JP, Boddaert N, Chadefaux-Vekemans B, Le Moyec L, Bastin J, Ottolenghi C, de Lonlay P. Pyruvate carboxylase deficiency: An underestimated cause of lactic acidosis. Mol Genet Metab Rep 2014. [PMID: 28649521 PMCID: PMC5471145 DOI: 10.1016/j.ymgmr.2014.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Pyruvate carboxylase (PC) is a biotin-containing mitochondrial enzyme that catalyzes the conversion of pyruvate to oxaloacetate, thereby being involved in gluconeogenesis and in energy production through replenishment of the tricarboxylic acid (TCA) cycle with oxaloacetate. PC deficiency is a very rare metabolic disorder. We report on a new patient affected by the moderate form (the American type A). Diagnosis was nearly fortuitous, resulting from the revision of an initial diagnosis of mitochondrial complex IV (C IV) defect. The patient presented with severe lactic acidosis and pronounced ketonuria, associated with lethargy at age 23 months. Intellectual disability was noted at this time. Amino acids in plasma and organic acids in urine did not show patterns of interest for the diagnostic work-up. In skin fibroblasts PC showed no detectable activity whereas biotinidase activity was normal. We had previously reported another patient with the severe form of PC deficiency and we show that she also had secondary C IV deficiency in fibroblasts. Different anaplerotic treatments in vivo and in vitro were tested using fibroblasts of both patients with 2 different types of PC deficiency, type A (patient 1) and type B (patient 2). Neither clinical nor biological effects in vivo and in vitro were observed using citrate, aspartate, oxoglutarate and bezafibrate. In conclusion, this case report suggests that the moderate form of PC deficiency may be underdiagnosed and illustrates the challenges raised by energetic disorders in terms of diagnostic work-up and therapeutical strategy even in a moderate form.
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Affiliation(s)
- F Habarou
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - A Brassier
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,Université Paris Descartes, Paris, France
| | - M Rio
- Département de Génétique, Hôpital Necker, APHP, Paris, France
| | | | - S Monnot
- Département de Génétique, Hôpital Necker, APHP, Paris, France.,IHU Imagine, UMR1163, France
| | - V Barbier
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France
| | - R Barouki
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - J P Bonnefont
- Département de Génétique, Hôpital Necker, APHP, Paris, France.,INSERM U781, Paris, France
| | - N Boddaert
- Service de Radiologie Pédiatrique, Hôpital Necker, APHP, Paris, France
| | - B Chadefaux-Vekemans
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - L Le Moyec
- INSERM U902, Université d'Evry Val d'Essonne, INSERM UBIAE U902, Boulevard François Miterrand, 91025 Evry, France
| | - J Bastin
- INSERM U1124, Université Paris Descartes, Paris, France
| | - C Ottolenghi
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,INSERM U1124, Université Paris Descartes, Paris, France.,Service de Biochimie Métabolomique et Protéomique, Hôpital Necker, APHP, Paris, France
| | - P de Lonlay
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker, APHP, Paris, France.,Université Paris Descartes, Paris, France.,INSERM U781, Paris, France
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13
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Menezes MJ, Riley LG, Christodoulou J. Mitochondrial respiratory chain disorders in childhood: Insights into diagnosis and management in the new era of genomic medicine. Biochim Biophys Acta Gen Subj 2014; 1840:1368-79. [DOI: 10.1016/j.bbagen.2013.12.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 12/10/2013] [Accepted: 12/18/2013] [Indexed: 12/26/2022]
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14
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Liang C, Ahmad K, Sue CM. The broadening spectrum of mitochondrial disease: shifts in the diagnostic paradigm. Biochim Biophys Acta Gen Subj 2013; 1840:1360-7. [PMID: 24239706 DOI: 10.1016/j.bbagen.2013.10.040] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 10/21/2013] [Accepted: 10/26/2013] [Indexed: 01/08/2023]
Abstract
BACKGROUND The diagnosis of mitochondrial disease requires a complex synthesis of clinical, biochemical, histological, and genetic investigations. An expanding number of mitochondrial diseases are being recognized, despite their phenotypic diversity, largely due to improvements in methods to detect mutations in affected individuals and the discovery of genes contributing to mitochondrial function. Improved understanding of the investigational pitfalls and the development of new laboratory methodologies that lead to a molecular diagnosis have necessitated the field to rapidly adopt changes to its diagnostic approach. SCOPE OF REVIEW We review the clinical, investigational and genetic challenges that have resulted in shifts to the way we define and diagnose mitochondrial disease. Incorporation of changes, including the use of fibroblast growth factor 21 (FGF-21) and next generation sequencing techniques, may allow affected patients access to earlier molecular diagnosis and management. MAJOR CONCLUSIONS There have been important shifts in the diagnostic paradigm for mitochondrial disease. Diagnosis of mitochondrial disease is no longer reliant on muscle biopsy alone, but should include clinical assessment accompanied by the use of serological biomarkers and genetic analysis. Because affected patients will be defined on a molecular basis, oligosymptomatic mutation carriers should be included in the spectrum of mitochondrial disease. Use of new techniques such as the measurement of serum FGF-21 levels and next-generation-sequencing protocols should simplify the diagnosis of mitochondrial disease. GENERAL SIGNIFICANCE Improvements in the diagnostic pathway for mitochondrial disease will result in earlier, cheaper and more accurate methods to identify patients with mitochondrial disease. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Christina Liang
- Department of Neurology, Royal North Shore Hospital, St. Leonards, New South Wales 2065, Australia
| | - Kate Ahmad
- Department of Neurology, Royal North Shore Hospital, St. Leonards, New South Wales 2065, Australia
| | - Carolyn M Sue
- Department of Neurology, Royal North Shore Hospital, St. Leonards, New South Wales 2065, Australia; Department of Neurogenetics, Kolling Institute of Medical Research, Royal North Shore Hospital and the University of Sydney, St. Leonards, New South Wales 2065, Australia.
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15
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Rodenburg RJT, Schoonderwoerd GC, Tiranti V, Taylor RW, Rötig A, Valente L, Invernizzi F, Chretien D, He L, Backx GPBM, Janssen KJGM, Chinnery PF, Smeets HJ, de Coo IF, van den Heuvel LP. A multi-center comparison of diagnostic methods for the biochemical evaluation of suspected mitochondrial disorders. Mitochondrion 2012; 13:36-43. [PMID: 23164799 PMCID: PMC3919210 DOI: 10.1016/j.mito.2012.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 11/01/2012] [Accepted: 11/07/2012] [Indexed: 12/05/2022]
Abstract
A multicenter comparison of mitochondrial respiratory chain and complex V enzyme activity tests was performed. The average reproducibility of the enzyme assays is 16% in human muscle samples. In a blinded diagnostic accuracy test in patient fibroblasts and SURF1 knock-out mouse muscle, each lab made the correct diagnosis except for two complex I results. We recommend that enzyme activities be evaluated based on ratios, e.g. with complex IV or citrate synthase activity. In spite of large variations in observed enzyme activities, we show that inter-laboratory comparison of patient sample test results is possible by using normalization against a control sample.
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Affiliation(s)
- R J T Rodenburg
- 774 Nijmegen Centre for Mitochondrial Disorders, Department of Pediatrics, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
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16
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Rafique MB, Cameron SD, Khan Q, Biliciler S, Zubair S. Anesthesia for children with mitochondrial disorders: a national survey and review. J Anesth 2012; 27:186-91. [PMID: 23007905 DOI: 10.1007/s00540-012-1488-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 08/30/2012] [Indexed: 12/19/2022]
Abstract
PURPOSE Mitochondrial diseases are a heterogeneous group of disorders. Patients with such diseases often need general anesthesia for diagnostic procedures and surgery; guidelines are lacking for the anesthetic care of these patients. METHODS We conducted a survey to investigate the current practices of pediatric anesthesiologists in the US in order to determine and document current practice. The survey consisted of twenty questions, including two demographic questions. A link to the survey was sent via email to members of the Society for Pediatric Anesthesia (2440), and was available online for 14 weeks. RESULTS Only 503 completed the survey: a response rate of 20.61 %. Among the responders, 93.2 % had children with mitochondrial disorders among their patients, but only 11 % had institutional guidelines for such cases in place. Among the responders, 80.3 % used the standard nil per os (NPO) status guidelines, while the rest give intravenous dextrose solution once NPO was in effect. Only 18.3 % took precautions for malignant hyperthermia during treatment. The majority of the practitioners chose sevoflurane as the safest inhaled agent for induction and maintenance (89.7 and 78.5 %, respectively). Regional anesthesia was deemed safe by 97.3 % of the responders. Lactated Ringer's solution was considered safe for these children by 49 %; only 47.8 % used dextrose-containing fluids for fluid replacement. The blood glucose was monitored by 72.7 %, and the majority (85 %) of this monitoring was done in a postanesthesia care unit. CONCLUSION Although the response rate was low, the majority of the responders provide care to these children routinely, so it can be inferred that the results of this survey are the closest published results to the true trend.
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Affiliation(s)
- Muhammad B Rafique
- Department of Anesthesiology, University of Texas-Medical School at Houston, 6431 Fannin St., MSB 5.020, Houston, TX 77030, USA.
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17
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Calvo SE, Compton AG, Hershman SG, Lim SC, Lieber DS, Tucker EJ, Laskowski A, Garone C, Liu S, Jaffe DB, Christodoulou J, Fletcher JM, Bruno DL, Goldblatt J, Dimauro S, Thorburn DR, Mootha VK. Molecular diagnosis of infantile mitochondrial disease with targeted next-generation sequencing. Sci Transl Med 2012; 4:118ra10. [PMID: 22277967 DOI: 10.1126/scitranslmed.3003310] [Citation(s) in RCA: 338] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Advances in next-generation sequencing (NGS) promise to facilitate diagnosis of inherited disorders. Although in research settings NGS has pinpointed causal alleles using segregation in large families, the key challenge for clinical diagnosis is application to single individuals. To explore its diagnostic use, we performed targeted NGS in 42 unrelated infants with clinical and biochemical evidence of mitochondrial oxidative phosphorylation disease. These devastating mitochondrial disorders are characterized by phenotypic and genetic heterogeneity, with more than 100 causal genes identified to date. We performed "MitoExome" sequencing of the mitochondrial DNA (mtDNA) and exons of ~1000 nuclear genes encoding mitochondrial proteins and prioritized rare mutations predicted to disrupt function. Because patients and healthy control individuals harbored a comparable number of such heterozygous alleles, we could not prioritize dominant-acting genes. However, patients showed a fivefold enrichment of genes with two such mutations that could underlie recessive disease. In total, 23 of 42 (55%) patients harbored such recessive genes or pathogenic mtDNA variants. Firm diagnoses were enabled in 10 patients (24%) who had mutations in genes previously linked to disease. Thirteen patients (31%) had mutations in nuclear genes not previously linked to disease. The pathogenicity of two such genes, NDUFB3 and AGK, was supported by complementation studies and evidence from multiple patients, respectively. The results underscore the potential and challenges of deploying NGS in clinical settings.
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Affiliation(s)
- Sarah E Calvo
- Center for Human Genetic Research and Department of Molecular Biology, Massachusetts General Hospital, 185 Cambridge Street, Sixth Floor, Boston, MA 02114, USA
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18
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Lankford J, Butler IJ, Koenig MK. Glucose transporter type I deficiency causing mitochondrial dysfunction. J Child Neurol 2012; 27:796-8. [PMID: 22156785 DOI: 10.1177/0883073811426503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mitochondrial disorders are varied in their clinical presentation and pathogenesis. Diagnosis is usually made clinically and genetic defects are often not identified. We present a 6-year-old female patient with a diagnosis of a mitochondrial disorder secondary to complex I deficiency with seizures and developmental delay from infancy. Glucose transporter deficiency was suspected after a lumbar puncture showed hypoglycorrhachia. Her disorder was confirmed genetically as a mutation in her solute carrier family 2, facilitated glucose transporter member 1 (SLCA2) gene. Delayed diagnosis led to delayed treatment, and neurologic sequelae may have been prevented by earlier recognition of this disorder.
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Affiliation(s)
- Jeremy Lankford
- Department of Pediatrics, Division of Child and Adolescent Neurology, The University of Texas Health Science Center, Houston, TX, USA
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19
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Corrigan NM, Shaw DWW, Richards TL, Estes AM, Friedman SD, Petropoulos H, Artru AA, Dager SR. Proton magnetic resonance spectroscopy and MRI reveal no evidence for brain mitochondrial dysfunction in children with autism spectrum disorder. J Autism Dev Disord 2012; 42:105-15. [PMID: 21404085 DOI: 10.1007/s10803-011-1216-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Brain mitochondrial dysfunction has been proposed as an etiologic factor in autism spectrum disorder (ASD). Proton magnetic resonance spectroscopic imaging ((1)HMRS) and MRI were used to assess for evidence of brain mitochondrial dysfunction in longitudinal samples of children with ASD or developmental delay (DD), and cross-sectionally in typically developing (TD) children at 3-4, 6-7 and 9-10 years-of-age. A total of 239 studies from 130 unique participants (54ASD, 22DD, 54TD) were acquired. (1)HMRS and MRI revealed no evidence for brain mitochondrial dysfunction in the children with ASD. Findings do not support a substantive role for brain mitochondrial abnormalities in the etiology or symptom expression of ASD, nor the widespread use of hyperbaric oxygen treatment that has been advocated on the basis of this proposed relationship.
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Affiliation(s)
- Neva M Corrigan
- Department of Radiology, University of Washington, Seattle, WA, USA
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20
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Frazier AE, Thorburn DR. Biochemical analyses of the electron transport chain complexes by spectrophotometry. Methods Mol Biol 2012; 837:49-62. [PMID: 22215540 DOI: 10.1007/978-1-61779-504-6_4] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In the diagnostic work-up of patients with suspected mitochondrial disease, evaluating the activity of the individual oxidative phosphorylation (OXPHOS) complexes is crucial. Here, we describe spectrophotometric assays for OXPHOS enzymology that can be applied to both tissue samples and cultured cells. These assays are designed to assess the enzymatic activity of the individual OXPHOS complexes I-V, along with the Krebs cycle enzyme citrate synthase as a mitochondrial control. As well, we include an assay for the coupled energy transfer between complexes II and III. Determining the enzymatic activities can be valuable in defining isolated or multicomplex disorders and may be relevant to the design of future molecular investigations.
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Affiliation(s)
- Ann E Frazier
- Murdoch Children's Research Institute, Parkville, VIC, Australia
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21
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Rodenburg RJT. Biochemical diagnosis of mitochondrial disorders. J Inherit Metab Dis 2011; 34:283-92. [PMID: 20440652 PMCID: PMC3063578 DOI: 10.1007/s10545-010-9081-y] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 03/16/2010] [Accepted: 03/17/2010] [Indexed: 11/04/2022]
Abstract
Establishing a diagnosis in patients with a suspected mitochondrial disorder is often a challenge. Both knowledge of the clinical spectrum of mitochondrial disorders and the number of identified disease-causing molecular genetic defects are continuously expanding. The diagnostic examination of patients requires a multi-disciplinary clinical and laboratory evaluation in which the biochemical examination of the mitochondrial functional state often plays a central role. In most cases, a muscle biopsy provides the best opportunity to examine mitochondrial function. In addition to activity measurements of individual oxidative phosphorylation enzymes, analysis of mitochondrial respiration, substrate oxidation, and ATP production rates is performed to obtain a detailed picture of the mitochondrial energy-generating system. On the basis of the compilation of clinical, biochemical, and other laboratory test results, candidate genes are selected for molecular genetic testing. In patients in whom an unknown genetic variant is identified, a compatible biochemical phenotype is often required to firmly establish the diagnosis. In addition to the current role of the biochemical analysis in the diagnostic examination of patients with a suspected mitochondria disorder, this report gives a future perspective on the biochemical diagnosis in view of both the expanding genotypes of mitochondrial disorders and the possibilities for high throughput molecular genetic diagnosis.
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Affiliation(s)
- Richard J T Rodenburg
- Nijmegen Center for Mitochondrial Disorders (NCMD), 656 Department of Pediatrics, Department of Laboratory Medicine, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
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22
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Wong LJC, Scaglia F, Graham BH, Craigen WJ. Current molecular diagnostic algorithm for mitochondrial disorders. Mol Genet Metab 2010; 100:111-7. [PMID: 20359921 DOI: 10.1016/j.ymgme.2010.02.024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Revised: 02/25/2010] [Accepted: 02/26/2010] [Indexed: 10/19/2022]
Abstract
Mitochondrial respiratory chain disorders (RCD) are a group of genetically and clinically heterogeneous diseases, due in part to the biochemical complexity of mitochondrial respiration and the fact that two genomes, one mitochondrial and one nuclear, encode the components of the respiratory chain. Because of the large number of genes involved, attempts to classify mitochondrial RCD incorporate clinical, biochemical, and histological criteria, in addition to DNA-based molecular diagnostic testing. While molecular testing is widely viewed as definitive, confirmation of the diagnosis by molecular methods often remains a challenge because of the large number of genes, the two genome complexity and the varying proportions of pathogenic mitochondrial DNA (mtDNA) molecules in a patient, a concept termed heteroplasmy. The selection of genes to be analyzed depends on the family history and clinical, biochemical, histopathological, and imaging results, as well as the availability of different tissues for analysis. Screening of common point mutations and large deletions in mtDNA is typically the first step. In cases where tissue-specific, recognizable clinical syndromes or characteristic RC complex deficiencies and histochemical abnormalities are observed, direct sequencing of the specific causative nuclear gene(s) can be performed on white blood cell DNA. Measurement of mtDNA content in affected tissues such as muscle and liver allows screening for mtDNA depletion syndromes. The ever-expanding list of known disease-causing genes will undoubtedly improve diagnostic accuracy and genetic counseling.
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Affiliation(s)
- Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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23
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Vasta V, Ng SB, Turner EH, Shendure J, Hahn SH. Next generation sequence analysis for mitochondrial disorders. Genome Med 2009; 1:100. [PMID: 19852779 PMCID: PMC2784303 DOI: 10.1186/gm100] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 09/04/2009] [Accepted: 10/23/2009] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Mitochondrial disorders can originate from mutations in one of many nuclear genes controlling the organelle function or in the mitochondrial genome (mitochondrial DNA (mtDNA)). The large numbers of potential culprit genes, together with the little guidance offered by most clinical phenotypes as to which gene may be causative, are a great challenge for the molecular diagnosis of these disorders. METHODS We developed a novel targeted resequencing assay for mitochondrial disorders relying on microarray-based hybrid capture coupled to next-generation sequencing. Specifically, we subjected the entire mtDNA genome and the exons and intron-exon boundary regions of 362 known or candidate causative nuclear genes to targeted capture and resequencing. We here provide proof-of-concept data by testing one HapMap DNA sample and two positive control samples. RESULTS Over 94% of the targeted regions were captured and sequenced with appropriate coverage and quality, allowing reliable variant calling. Pathogenic mutations blindly tested in patients' samples were 100% concordant with previous Sanger sequencing results: a known mutation in Pyruvate dehydrogenase alpha 1 subunit (PDHA1), a novel splicing and a known coding mutation in Hydroxyacyl-CoA dehydrogenase alpha subunit (HADHA) were correctly identified. Of the additional variants recognized, 90 to 94% were present in dbSNP while 6 to 10% represented new alterations. The novel nonsynonymous variants were all in heterozygote state and mostly predicted to be benign. The depth of sequencing coverage of mtDNA was extremely high, suggesting that it may be feasible to detect pathogenic mtDNA mutations confounded by low level heteroplasmy. Only one sequencing lane of an eight lane flow cell was utilized for each sample, indicating that a cost-effective clinical test can be achieved. CONCLUSIONS Our study indicates that the use of next generation sequencing technology holds great promise as a tool for screening mitochondrial disorders. The availability of a comprehensive molecular diagnostic tool will increase the capacity for early and rapid identification of mitochondrial disorders. In addition, the proposed approach has the potential to identify new mutations in candidate genes, expanding and redefining the spectrum of causative genes responsible for mitochondrial disorders.
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Affiliation(s)
- Valeria Vasta
- Seattle Children's Research Institute, 1900 9th Ave, Seattle, WA 98101, USA.
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24
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Inherited disorders affecting mitochondrial function are associated with glutathione deficiency and hypocitrullinemia. Proc Natl Acad Sci U S A 2009; 106:3941-5. [PMID: 19223582 DOI: 10.1073/pnas.0813409106] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Disorders affecting mitochondria, including those that directly affect the respiratory chain function or result from abnormalities in branched amino acid metabolism (organic acidemias), have been shown to be associated with impaired redox balance. Almost all of the evidence underlying this conclusion has been obtained from studies on patient biopsies or animal models. Since the glutathione (iGSH) system provides the main protection against oxidative damage, we hypothesized that untreated oxidative stress in individuals with mitochondrial dysfunction would result in chronic iGSH deficiency. We confirm this hypothesis here in studies using high-dimensional flow cytometry (Hi-D FACS) and biochemical analysis of freshly obtained blood samples from patients with mitochondrial disorders or organic acidemias. T lymphocyte subsets, monocytes and neutrophils from organic acidemia and mitochondrial patients who were not on antioxidant supplements showed low iGSH levels, whereas similar subjects on antioxidant supplements showed normal iGSH. Measures of iROS levels in blood were insufficient to reveal the chronic oxidative stress in untreated patients. Patients with organic acidemias showed elevated plasma protein carbonyls, while plasma samples from all patients tested showed hypocitrullinemia. These findings indicate that measurements of iGSH in leukocytes may be a particularly useful biomarker to detect redox imbalance in mitochondrial disorders and organic acidemias, thus providing a relatively non-invasive means to monitor disease status and response to therapies. Furthermore, studies here suggest that antioxidant therapy may be useful for relieving the chronic oxidative stress that otherwise occurs in patients with mitochondrial dysfunction.
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25
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Koenig MK. Presentation and diagnosis of mitochondrial disorders in children. Pediatr Neurol 2008; 38:305-13. [PMID: 18410845 PMCID: PMC3099432 DOI: 10.1016/j.pediatrneurol.2007.12.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Revised: 11/07/2007] [Accepted: 12/03/2007] [Indexed: 02/04/2023]
Abstract
The first disorder of mitochondrial function was described by Luft in 1959. Over the ensuing decades, multiple cases of mitochondrial dysfunction were reported, and the term "mitochondrial disorder" arose to describe any defect in the mitochondrial electron transport chain. The sequence of the mitochondrial genome was elucidated in 1981 by Anderson et al., and during the next 20 years, >200 pathogenic point mutations, deletions, insertions, and rearrangements were described. Most of the original cases were adults, and the diagnosis of a mitochondrial disorder in an adult patient became relatively straightforward. Adults present with well-defined "mitochondrial syndromes" and generally carry mitochondrial DNA mutations that are easily identified. Children with mitochondrial disorders are much harder to define. Children are more likely to have a nuclear DNA mutation, whereas the "classic" syndromic findings tend to be absent. This review describes both the varying presentations of mitochondrial disorders and the common laboratory, imaging, and pathologic findings related to children.
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Affiliation(s)
- Mary Kay Koenig
- Department of Pediatrics and Department of Neurology, University of Texas Health Science Center, 6431 Fannin St., Houston, TX 77030, USA.
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Haas RH, Parikh S, Falk MJ, Saneto RP, Wolf NI, Darin N, Wong LJ, Cohen BH, Naviaux RK. The in-depth evaluation of suspected mitochondrial disease. Mol Genet Metab 2008; 94:16-37. [PMID: 18243024 PMCID: PMC2810849 DOI: 10.1016/j.ymgme.2007.11.018] [Citation(s) in RCA: 249] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 11/21/2007] [Accepted: 11/21/2007] [Indexed: 12/12/2022]
Abstract
Mitochondrial disease confirmation and establishment of a specific molecular diagnosis requires extensive clinical and laboratory evaluation. Dual genome origins of mitochondrial disease, multi-organ system manifestations, and an ever increasing spectrum of recognized phenotypes represent the main diagnostic challenges. To overcome these obstacles, compiling information from a variety of diagnostic laboratory modalities can often provide sufficient evidence to establish an etiology. These include blood and tissue histochemical and analyte measurements, neuroimaging, provocative testing, enzymatic assays of tissue samples and cultured cells, as well as DNA analysis. As interpretation of results from these multifaceted investigations can become quite complex, the Diagnostic Committee of the Mitochondrial Medicine Society developed this review to provide an overview of currently available and emerging methodologies for the diagnosis of primary mitochondrial disease, with a focus on disorders characterized by impairment of oxidative phosphorylation. The aim of this work is to facilitate the diagnosis of mitochondrial disease by geneticists, neurologists, and other metabolic specialists who face the challenge of evaluating patients of all ages with suspected mitochondrial disease.
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Affiliation(s)
- Richard H. Haas
- Departments of Neurosciences & Pediatrics, University of California San Diego, La Jolla, CA and Rady Children's Hospital San Diego, San Diego, CA
- Corresponding Author: Richard H. Haas, MB, BChir, MRCP, Professor of Neurosciences and Pediatrics, University of California San Diego, T. 858-822-6700; F. 858-822-6707;
| | - Sumit Parikh
- Division of Neuroscience, The Cleveland Clinic, Cleveland, OH
| | - Marni J. Falk
- Division of Human Genetics, The Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA
| | - Russell P. Saneto
- Division of Pediatric Neurology, Children's Hospital and Regional Medical Center, University of Washington, Seattle, WA
| | - Nicole I. Wolf
- Department of Child Neurology, University Children's Hospital, Heidelberg, Germany
| | - Niklas Darin
- Division of Child Neurology, The Queen Silvia Children's Hospital, Göteborg, Sweden
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Bruce H. Cohen
- Division of Neuroscience, The Cleveland Clinic, Cleveland, OH
| | - Robert K. Naviaux
- Departments of Medicine and Pediatrics, Division of Medical and Biochemical Genetics, University of California San Diego, La Jolla, CA and Rady Children's Hospital San Diego, San Diego, CA
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Neuroradiologic findings in children with mitochondrial disorder: correlation with mitochondrial respiratory chain defects. Eur Radiol 2008; 18:1741-8. [DOI: 10.1007/s00330-008-0921-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 02/03/2008] [Indexed: 10/22/2022]
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Kirby DM, Thorburn DR, Turnbull DM, Taylor RW. Biochemical assays of respiratory chain complex activity. Methods Cell Biol 2007; 80:93-119. [PMID: 17445690 DOI: 10.1016/s0091-679x(06)80004-x] [Citation(s) in RCA: 281] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Denise M Kirby
- Mitochondrial Research Group, School of Neurology, Neurobiology and Psychiatry, The Medical School, Framlington Place, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom
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Hui J, Kirby DM, Thorburn DR, Boneh A. Decreased activities of mitochondrial respiratory chain complexes in non-mitochondrial respiratory chain diseases. Dev Med Child Neurol 2006; 48:132-6. [PMID: 16417669 DOI: 10.1017/s0012162206000284] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/03/2005] [Indexed: 11/06/2022]
Abstract
The aim of this study was to illustrate the difficulties in establishing a diagnosis of mitochondrial respiratory chain (MRC) disorders based on clinical grounds in combination with intermediate activities of the MRC enzyme complexes. We reviewed retrospectively all medical and laboratory records of patients initially considered likely to have MRC disorders on clinical grounds, and subsequently diagnosed with other disorders (n = 20; 11 males, 9 females). Data were retrieved from hospital records, referral letters, and results of enzymatic analysis at a reference laboratory. Clinical symptoms included developmental delay, epilepsy, hypotonia, movement disorder, spastic quadriplegia, tetany, microcephaly, visual problems, carpopedal spasms, dysmorphism, hearing loss, muscle weakness and rhabdomyolysis, and fulminant hepatitis. Blood and cerebrospinal fluid lactate levels were elevated in 13/20 and 9/20 respectively. One or more MRC complex activities (expressed as ratios relative to citrate synthase and/or complex II activity) were less than 50% of control mean activity in 11/20 patients (including patients with deficiencies of pyruvate dehydrogenase complex, pantothenate kinase, holocarboxylase synthetase, long-chain hydroxy acyl-CoA dehydrogenase, molybdenum co-factor, and neonatal haemochromatosis). One patient had a pattern suggestive of mitochondrial proliferation. We conclude that intermediate results of MRC enzymes should be interpreted with caution and clinicians should be actively looking for other underlying diagnoses.
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Affiliation(s)
- Joannie Hui
- Metabolic Service, Genetic Health Services, Victoria Royal Children's Hospital, Australia
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Glass HC, Feigenbaum A, Clarke JTR. A study on the nature of genetic metabolic practice at a major paediatric referral centre. J Inherit Metab Dis 2006; 29:175-8. [PMID: 16601885 DOI: 10.1007/s10545-006-0118-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
A retrospective chart review of new paediatric patients seen during the calendar year 1998 by specialists of the Division of Clinical and Metabolic Genetics of the Hospital for Sick Children in Toronto, the largest such referral centre in the country, showed that 81% of specific genetic metabolic diagnoses were made within one month of being seen in consultation by one of the consultants of the programme. In 5% of cases, a specific diagnosis was not reached 4 years after initial consultation. We concluded from this study that the specific diagnosis of inborn errors of metabolism at a major medical genetic referral centre tended to be made quickly, or never. Some of the causes of delays in diagnosis include (1) the lack of ready access to existing diagnostic laboratory testing; (2) technical barriers to the identification of specific metabolic or genetic defects; and (3) incomplete knowledge of genetic defects causing inherited metabolic diseases.
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Affiliation(s)
- H C Glass
- Division of Pediatric Neurology, Alberta Children's Hospital, University of Calgary, Alberta
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Kramer KA, Oglesbee D, Hartman SJ, Huey J, Anderson B, Magera MJ, Matern D, Rinaldo P, Robinson BH, Cameron JM, Hahn SH. Automated spectrophotometric analysis of mitochondrial respiratory chain complex enzyme activities in cultured skin fibroblasts. Clin Chem 2005; 51:2110-6. [PMID: 16141288 DOI: 10.1373/clinchem.2005.050146] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Mitochondrial respiratory chain complex (RCC) disorders may occur as commonly as 1 in 8500 individuals. Because of the great variability of phenotypic presentations, measurement of individual RCC enzyme activities is a crucial diagnostic process. Current assay methods are time-consuming and labor-intensive and thus constitute a major impediment to clinical practice. A method with a faster turnaround time would therefore be beneficial. METHOD We developed an automated spectrophotometric method for measuring the respiratory chain enzyme activities of complex I, complex II + III, and complex IV with the Hitachi 912, an automated spectrophotometer. Mitochondrial citrate synthase was also determined for normalization of the RCC activities. RESULTS A blinded method comparison with samples from an external testing center yielded a 91% concordance of interpretations. Mean intraassay imprecision (as CV; n = 20) in a single batch analysis of each RCC was 5.9%. Interassay imprecision, evaluated on 2 samples harvested and analyzed 3 times each, gave mean CVs of 10%-18%. CONCLUSIONS With this automated method, a panel of RCC enzyme activities can be determined in <2 h. In addition, an immunoblot assay using monoclonal antibodies against specific subunits of RCC enzyme complexes can be informative in cases of borderline enzyme activity. Our results suggest that in vitro diagnosis of RCC enzyme deficiencies in skin fibroblasts is an effective alternative to invasive muscle biopsy.
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Affiliation(s)
- Karen A Kramer
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Thorburn DR, Sugiana C, Salemi R, Kirby DM, Worgan L, Ohtake A, Ryan MT. Biochemical and molecular diagnosis of mitochondrial respiratory chain disorders. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1659:121-8. [PMID: 15576043 DOI: 10.1016/j.bbabio.2004.08.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 08/16/2004] [Accepted: 08/16/2004] [Indexed: 12/25/2022]
Abstract
Biochemical diagnosis of mitochondrial respiratory chain disorders requires caution to avoid misdiagnosis of secondary enzyme defects, and can be improved by the use of conservative diagnostic criteria. Pathogenic mutations causing mitochondrial disorders have now been identified in more than 30 mitochondrial DNA (mtDNA) genes encoding respiratory chain subunits, ribosomal- and t-RNAs. mtDNA mutations appear to be responsible for most adult patients with mitochondrial disease and approximately a quarter of paediatric patients. A family history suggesting maternal inheritance is the exception rather than the norm for children with mtDNA mutations, many of whom have de novo mutations. Prenatal diagnosis and pre-implantation genetic diagnosis can be offered to some women at risk of transmitting a mtDNA mutation, particularly those at lower recurrence risk. Mutations in more than 30 nuclear genes, including those encoding for respiratory chain subunits and assembly factors, have now been shown to cause mitochondrial disorders, creating difficulties in prioritising which genes should be studied by mutation analysis in individual patients. A number of approaches offer promise to guide the choice of candidate genes, including Blue Native-PAGE immunoblotting and microarray expression analysis.
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Affiliation(s)
- David R Thorburn
- Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria 3052 Australia.
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Rutledge JC, Finn LS. Pediatric mitochondrial disease: do we have the energy to make the diagnosis? Pediatr Dev Pathol 2004; 7:641-5. [PMID: 15630536 DOI: 10.1007/s10024-004-5049-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Accepted: 07/26/2004] [Indexed: 11/25/2022]
Affiliation(s)
- Joe C Rutledge
- Department of Laboratory Medicine, University of Washington School of Medicine and Children's Hospital and Regional Medical Center, 4800 Sand Point Way NE, Seattle, WA 98105, USA.
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Affiliation(s)
- Kathleen Patterson
- University of Washington School of Medicine and Children's Hospital and Regional Medical Center, 4800 Sandpoint Way NE, Seattle, WA 98105, USA.
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Scaglia F, Towbin JA, Craigen WJ, Belmont JW, Smith EO, Neish SR, Ware SM, Hunter JV, Fernbach SD, Vladutiu GD, Wong LJC, Vogel H. Clinical spectrum, morbidity, and mortality in 113 pediatric patients with mitochondrial disease. Pediatrics 2004; 114:925-31. [PMID: 15466086 DOI: 10.1542/peds.2004-0718] [Citation(s) in RCA: 310] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The aim of this study was to elucidate the frequency of major clinical manifestations in children with mitochondrial disease and establish their clinical course, prognosis, and rates of survival depending on their clinical features. METHODS We performed a retrospective review of the medical records of 400 patients who were referred for evaluation of mitochondrial disease. By use of the modified Walker criteria, only patients who were assigned a definite diagnosis were included in the study. RESULTS A total of 113 pediatric patients with mitochondrial disease were identified. A total of 102 (90%) patients underwent a muscle biopsy as part of the diagnostic workup. A significant respiratory chain (RC) defect, according to the diagnostic criteria, was found in 71% of the patients who were evaluated. In this cohort, complex I deficiency (32%) and combined complex I, III, and IV deficiencies (26%) were the most common causes of RC defects, followed by complex IV (19%), complex III (16%), and complex II deficiencies (7%). Pathogenic mitochondrial DNA abnormalities were found in 11.5% of the patients. A substantial fraction (40%) of patients with mitochondrial disorders exhibited cardiac disease, diagnosed by Doppler echocardiography; however, the majority (60%) of patients had predominant neuromuscular manifestations. No correlation between the type of RC defect and the clinical presentation was observed. Overall, the mean age at presentation was 40 months. However, the mean age at presentation was 33 months in the cardiac group and 44 months in the noncardiac group. Twenty-six (58%) patients in the cardiac group exhibited hypertrophic cardiomyopathy, 29% had dilated cardiomyopathy, and the remainder (13%) had left ventricular noncompaction. Patients with cardiomyopathy had an 18% survival rate at 16 years of age. Patients with neuromuscular features but no cardiomyopathy had a 95% survival at the same age. CONCLUSIONS This study gives strong support to the view that in patients with RC defects, cardiomyopathy is more common than previously thought and tends to follow a different and more severe clinical course. Although with a greater frequency than previously reported, mitochondrial DNA mutations were found in a minority of patients, emphasizing that most mitochondrial disorders of childhood follow a Mendelian pattern of inheritance.
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Affiliation(s)
- Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Taylor RW, Schaefer AM, Barron MJ, McFarland R, Turnbull DM. The diagnosis of mitochondrial muscle disease. Neuromuscul Disord 2004; 14:237-45. [PMID: 15019701 DOI: 10.1016/j.nmd.2003.12.004] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2003] [Revised: 11/24/2003] [Accepted: 12/23/2003] [Indexed: 10/26/2022]
Abstract
Mitochondrial respiratory chain abnormalities are an important cause of neuromuscular disease and may be due to defects of either the mitochondrial or nuclear genome. On account of the clinical and genetic heterogeneity exhibited by the mitochondrial myopathies, their investigation and diagnosis remains a challenge, requiring a combination of techniques including muscle histochemistry, biochemical assessment of respiratory chain function and molecular genetic studies. Here, we describe a step-by-step approach to the clinical and laboratory diagnosis of mitochondrial muscle disease, highlighting the many potential problems that can hinder reaching the correct diagnosis.
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Affiliation(s)
- Robert W Taylor
- Mitochondrial Research Group, School of Neurology, Neurobiology and Psychiatry, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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Abstract
Mitochondriopathies (MCPs) are either due to sporadic or inherited mutations in nuclear or mitochondrial DNA located genes (primary MCPs), or due to exogenous factors (secondary MCPs). MCPs usually show a chronic, slowly progressive course and present with multiorgan involvement with varying onset between birth and late adulthood. Although several proteins with signalling, assembling, transport, enzymatic function can be impaired in MCP, most frequently the activity of the respiratory chain (RC) protein complexes is primarily or secondarily affected, leading to impaired oxygen utilization and reduced energy production. MCPs represent a diagnostic challenge because of their wide variation in presentation and course. Systems frequently affected in MCP are the peripheral nervous system (myopathy, polyneuropathy, lactacidosis), brain (leucencephalopathy, calcifications, stroke-like episodes, atrophy with dementia, epilepsy, upper motor neuron signs, ataxia, extrapyramidal manifestations, fatigue), endocrinium (short stature, hyperhidrosis, diabetes, hyperlipidaemia, hypogonadism, amenorrhoea, delayed puberty), heart (impulse generation or conduction defects, cardiomyopathy, left ventricular non-compaction heart failure), eyes (cataract, glaucoma, pigmentary retinopathy, optic atrophy), ears (deafness, tinnitus, peripheral vertigo), guts (dysphagia, vomiting, diarrhoea, hepatopathy, pseudo-obstruction, pancreatitis, pancreas insufficiency), kidney (renal failure, cysts) and bone marrow (sideroblastic anaemia). Apart from well-recognized syndromes, MCP should be considered in any patient with unexplained progressive multisystem disorder. Although there is actually no specific therapy and cure for MCP, many secondary problems require specific treatment. The rapidly increasing understanding of the pathophysiological background of MCPs may further facilitate the diagnostic approach and open perspectives to future, possibly causative therapies.
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Affiliation(s)
- J Finsterer
- Neurological Department, Krankenanstalt Rudolfstiftung, Vienna, Austria.
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Sadleir LG, Connolly MB, Applegarth D, Hendson G, Clarke L, Rakshi C, Farrell K. Spasms in children with definite and probable mitochondrial disease*. Eur J Neurol 2004; 11:103-10. [PMID: 14748770 DOI: 10.1046/j.1351-5101.2003.00724.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The diagnosis of mitochondrial encephalomyopathies is complex and a system for classification of the diagnosis as definite, probable, and possible has been proposed. The objective of this study was to explore the spectrum of epileptic disorders associated with probable and definite mitochondrial disease in children using this classification system. The patient population with mitochondrial disease and epilepsy was selected from a tertiary care children's hospital. Interictal electroencephalograms and video-EEG recordings were used to characterize seizure types. Ten children fulfilled the criteria for probable or definite mitochondrial disease and had epilepsy. Four had siblings with a similar clinical phenotype. Spasms were the most common seizure type and were the initial seizure type in seven patients and two siblings. Four patients had only partial seizures, with or without generalization, and one patient had seizures that were difficult to classify. Blood lactate concentrations were elevated consistently in patients with partial seizures alone but were occasionally normal in children with spasms. Spasms were the most common presenting seizure type in children with probable and definite mitochondrial disease.
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Affiliation(s)
- L G Sadleir
- Department of Paediatrics, Wellington School of Medicine, University of Otago, Wellington, New Zealand.
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Abstract
Disorders of mitochondrial oxidative phosphorylation (OXPHOS) are renowned for their variability in clinical features and genetic causes. This makes it difficult to determine their true prevalence, but recent studies have documented a minimum birth prevalence of 13.1/100000 or 1/7634 for oxidative phosphorylation disorders with onset at any age. This clearly remains an underestimate but it indicates that oxidative phosphorylation disorders can be regarded as the most common group of inborn errors of metabolism. Pathogenic mutations causing human oxidative phosphorylation disorders have now been identified in more than 30 of the 37 mitochondrial DNA genes and in more than 30 nuclear genes. Most of the nuclear gene defects cause autosomal recessive diseases, but autosomal dominant and X-linked disorders also occur. It is likely that at least another 30, and perhaps over 100, nuclear-encoded oxidative phosphorylation disorders await identification. Oxidative phosphorylation genetics are complex and there appear to be a number of common misconceptions about mitochondrial DNA mutations that may impede optimal investigation and management of patients. In our experience, mitochondrial DNA mutations are not a negligible cause of OXPHOS disorders in children but account for 20-25% of cases. Similarly, a family history suggesting maternal inheritance is the exception rather than the norm for children with mitochondrial DNA mutations, many of whom have de novo mutations. Only some mitochondrial DNA mutations disappear from cultured cells, so deficient enzyme activity in fibroblasts does not imply the presence of a nuclear defect. Finally, it is still widely thought that there are very few reproductive options that can be offered to women at risk of transmitting a mitochondrial DNA mutation. While a cautious approach is needed, there is now a consensus that prenatal diagnosis should be offered to some women, particularly those at lower recurrence risk. Preimplantation genetic diagnosis can also be an option.
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Affiliation(s)
- D R Thorburn
- The Murdoch Children's Research Institute and Genetic Health Services Victoria, Royal Children's Hospital, and Department of Paediatrics, University of Melbourne, Melbourne, Australia.
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Skladal D, Sudmeier C, Konstantopoulou V, Stöckler-Ipsiroglu S, Plecko-Startinig B, Bernert G, Zeman J, Sperl W. The clinical spectrum of mitochondrial disease in 75 pediatric patients. Clin Pediatr (Phila) 2003; 42:703-10. [PMID: 14601919 DOI: 10.1177/000992280304200806] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The clinical presentation of mitochondrial disorders in childhood is highly variable causing difficulties in diagnosis and management. We assessed records of 75 children (48 male, 27 female) with a biochemically and/or molecularly established mitochondrial disorder in a retrospective, multicentric study. The predominant biochemical defect was an isolated respiratory chain complex IV, followed by respiratory chain complex I, combined respiratory chain, and isolated pyruvate dehydrogenase complex (PDHC) deficiencies. For the 75 patients, the predominant clinical presentations were a nonspecific encephalomyopathy (n = 34) and Leigh syndrome (n = 17). Classical mitochondrial syndromes with associated mutations of the mitochondrial DNA were rare (n = 12). Eleven children had a lethal infantile mitochondrial disease (LIMD). This group comprised a considerable variety of clinical pictures, and the cohort was big enough to show the high frequency and wide spectrum of nonneuromuscular symptoms in mitochondrial disorders in childhood.
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Affiliation(s)
- D Skladal
- University Children's Hospital, Innsbruck, Austria
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Niers L, van den Heuvel L, Trijbels F, Sengers R, Smeitink J. Prerequisites and strategies for prenatal diagnosis of respiratory chain deficiency in chorionic villi. J Inherit Metab Dis 2003; 26:647-58. [PMID: 14707513 DOI: 10.1023/b:boli.0000005605.57420.b4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Prenatal diagnosis for respiratory chain deficiencies is a complex procedure that requires a thorough diagnostic work-up of the index patient. This includes confirmation of the clinical and metabolic evaluations through histological and enzymatic examinations of tissue biopsies. Prenatal diagnosis currently relies on biochemical assays of respiratory chain complexes in chorionic villi or amniocytes and is possible by mutation analysis of nuclear genes in a limited but increasing proportion of cases. Based on a recent survey of prenatal diagnosis in families with complex I and complex IV deficiencies, performed at Nijmegen Centre for Mitochondrial Disorders (NCMD), prerequisites and strategies for performing prenatal diagnosis have been developed to increase reliability. Biochemical investigations in chorionic villi can be done reliably if the respiratory chain enzyme deficiency is expressed in both skeletal muscle and skin fibroblasts to rule out tissue specificity. No mitochondrial DNA defects must be suspected or established. The NCMD does not offer prenatal diagnosis until all the prerequisites have been confirmed. We expect prenatal diagnosis at the molecular level to become more feasible in time as the mutational spectrum broadens with advances in medical research.
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Affiliation(s)
- L Niers
- Department of Paediatrics, Nijmegen Centre for Mitochondrial Disorders, The Netherlands
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Abstract
The number of genes known to be involved in mitochondrial energy production and the elucidation of the function of their individual transcripts is still increasing. Although at this stage it is impossible to predict the number of human genes necessary for mitochondrial biogenesis and maintenance, the total number in humans will most probably exceed the number of mitochondrial genes found in, for example, the budding yeast, which is about 800. Without doubt we have only seen the tip of the iceberg of the clinical spectrum of mitochondrial disorders. Recent findings such as mutations in structural complex II genes in certain tumours emphasize the need to think outside the classical clinical presentation. We propose the consideration of a mitochondrial disorder in every chronic, intermittent or progressive disorder with single system or multisystem involvement, even if lactic acid is normal, and discuss such dilemmas as whether we should 'scrape the barrel' in every patient that are raised by this statement. The characterization of mitochondrial and nuclear DNA mutations in patients with enzymatically established mitochondrial defects has taught us that several of the current clinical and diagnostic assumptions have to be altered or even eliminated. The most challenging future task will be the development of new diagnostic criteria covering the expanding clinical spectrum of mitochondrial disorders.
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Affiliation(s)
- J A M Smeitink
- Nijmegen Center for Mitochondrial Disorders, Department of Paediatrics, University Medical Center Nijmegen, The Netherlands.
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44
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Borchert A, Wolf NI, Wilichowski E. Current concepts of mitochondrial disorders in childhood. Semin Pediatr Neurol 2002; 9:151-9. [PMID: 12138999 DOI: 10.1053/spen.2002.33800] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Respiratory chain deficiencies have long been regarded as rare neuromuscular diseases mostly originating from mutations in the mitochondrial genome. Research in the last years has created quite a different picture. The clinical spectrum has expanded to multiorgan disease manifestation, with an estimated minimum incidence in children of 1:11,000. Mutations in the nuclear genome have been discovered in recent years, thereby adding mendelian genetics to the broadened spectrum of mitochondrial disease. This review summarizes recent advances in mitochondrial disorders with a special focus on childhood presentation and therapeutic approaches that may prove useful in the future.
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Affiliation(s)
- Astrid Borchert
- Department of Neuropediatrics, University Children's Hopsital, Heidelberg, Germany
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